The purpose of this project is to conduct research in statistical methods and computer techniques with particular emphasis on those appropriate for analyzing data from clinical and diagnostic trials and epidemiological studies of cancer. Many of the problems studied under this project arise from the consultative activities of the Section (see Z01CP04260-23B). During the past year methods have been proposed to estimate the total number of oncogenes for a given species based on the number of distinct oncogenes observed in laboratory studies. Logistic regression methods have been developed for analyzing data consisting of a sequence of binary responses for each experimental subject. These methods permit adjustment both for initial and for time-dependent covariates. Members of the Section have taken two different approaches to the difficult statistical problem of comparing different staging systems for chronic disease. One method postulates a proportional hazards model and uses likelihood ratio tests for comparing each model alone with a comprehensive model incorporating variables representing the stages in the separate systems. The other method is non-parametric and relies on bootstrap methods to compare various measures of good prediction. In the area of survival analysis, work has continued on methods of analysis appropriate for situations in which censoring mechanisms may not be independent of the death process and a new measure of censoring dependence has been defined. Two special cases of non-independent censoring have been studied, situations in which characteristics of patients entering a study change over time and where biased follow-up occurs due to under-reporting of deaths. Other work has concerned rules for terminating accrual in clinical trials, comparisons of various methods for setting confidence limits on estimates of median survival, methods for constructing adjusted survival curves and estimating their variances, assessment of diagnostic tests, and estimation of attributable risk for multiple factors.